Penumbral decay observed in active region NOAA 12585

Abstract

The physical conditions leading the sunspot penumbra decay are poorly understood so far. We investigate the photospheric magnetic and velocity properties of a sunspot penumbra during the decay phase to advance the current knowledge of the conditions leading to this process. A penumbral decay was observed with the CRISP instrument at the Swedish 1m Solar Telescope on 2016 September 4 and 5 in active region NOAA 12585. During these days, full-Stokes spectropolarimetric scans along the Fe I 630 nm line pair were acquired over more than one hour. We inverted these observations with the VFISV code in order to obtain the evolution of the magnetic and velocity properties. We complement the study with data from instruments onboard the Solar Dynamics Observatory and Hinode space missions. The studied penumbra disappears progressively in both time and space. The magnetic flux evolution seems to be linked to the presence of Moving Magnetic Features (MMFs). Decreasing Stokes V signals are observed. Evershed flows and horizontal fields were detected even after the disappearance of the penumbral sector. The analyzed penumbral decay seems to result from the interaction between opposite polarity fields in type III MMFs and penumbra, while the presence of overlying canopies rules the evolution in the different penumbral sectors.

13 pages, 11 figures, accepted for publication in A&A

References in corpus (19)

• The Solar Optical Telescope for the Hinode Mission: An Overview
• The Solar Orbiter mission -- Science overview
• The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs -- Space-weather HMI Active Region Patches
• CRISP Spectropolarimetric Imaging of Penumbral Fine Structure
• CRISPRED: A data pipeline for the CRISP imaging spectropolarimeter
• Intermittent reconnection and plasmoids in UV bursts in the low solar atmosphere
• Detection of sea-serpent field lines in sunspot penumbrae
• Three-dimensional structure of a sunspot light bridge
• Ellerman bombs and UV bursts: reconnection at different atmospheric layers
• Flow Field Evolution of a Decaying Sunspot
• Spectropolarimetry of a decaying sunspot penumbra
• Spatial deconvolution of spectropolarimetric data: an application to quiet Sun magnetic elements
• Normal and counter Evershed flows in the photospheric penumbra of a sunspot. SPINOR 2D inversions of Hinode-SOT/ SP observations
• On the formation of a stable penumbra in a region of flux emergence in the Sun
• Observational Evidence of a Flux Rope within a Sunspot Umbra
• Evershed and counter-Evershed flows in sunspot MHD simulations
• Restoring process of sunspot penumbra
• Kinematics and Magnetic Properties of a Light Bridge in a Decaying Sunspot
• Plasma flows and magnetic field interplay during the formation of a pore

Cited by in corpus (6)

• The European Solar Telescope
• The role of the chromospheric magnetic canopy in the formation of a sunspot penumbra
• Investigating the effect of solar ambient and data characteristics on Ca II K observations and line profile measurements
• The Decay of Two Adjacent Sunspots Associated with Moving Magnetic Features
• Evolution of the flow field in decaying active regions II. Converging flows at the periphery of naked spots
• Decay of a photospheric transient filament at the boundary of a pore and the chromospheric response